I have not had this exact issue, but similar. On my computer I use Chrome with my v7 environment. Lately I've noticed that when I @mention someone, sometimes instead of adding the @mention it navigates to their profile and when I go back, my post is completely gone and Recover is not an option. I also have issues with both Chrome and Safari on my ipad ... when I type, it adds the first character typed twice and I cannot go back and edit anything. It doesn't disappear, it just won't let me edit and if I try it locks up and I have to quit and start over.